Apparatus for fixing plaster-work to ceilings.



PATBNTED AUG. 28, 1906.

M. LAU. APPARATUS FOR FIXG PLSTER WORK T0 GEILINGS.

APPLICATION IILBD APB.24.1905.

ma nomma Pz .A wAsmunmN, o. c.

UNITED STATES,

PATENT OFFICE.

MORITZ LAU, OF BRESLAU, GERMANY.

Specification of Letters Patent.

Patented Aug. 28, 1906.

Application filed April 24, 1905. Serial No. 257,171.

Be it known that I, MORITZ LAU, a subject of the German Emperor, residing at 98 Sternstrasse, Breslau, Germany, have invented certain new and useful Improvements in Apparatus for Fixing Plaster-York to Ceilings; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

In fixing plaster-work to ceilings the practice hitherto has been to roughen the back of the iinished piece of plaster-work at the place where it is to be fixed, to apply fresh plaster to it, and then to lay it against the ceiling, when it is easily `fixed by means of screws or the likeI` The fresh plaster adheres on the one side to the ceiling and on the other side to the piece of work, which is thus fixed to the ceiling. This method can be successfully employed in the case of ceilings with wooden beams, but is not at all suitable for the new concrete ceilin rs. Even if the concrete ceilinfi be well roug ened before the piece of work is laid on this method completely fails. The layer of plaster which is freshly laid on the finished piece of work and is intended for fixing it to the ceiling must for practical reasons be exceedingly thin. As soon, however, as this thin layer is put on the piece of plaster-work the moisture contained in it is absorbed thereby, and when the piece of work is laid against the ceiling the freshly-applied layer of plaster is deficient in the moisture which it has to give off to the body of concrete in order to insure the fixing of the piece of work thereto. In the case of concrete ceilings, therefore, the piece of work has to be 'fixed by screwing. As, however, the screws cannot be directly screwed into the concrete, wooden dowels having first to be let into the ceiling, this method of fixing the plaster-work is troublesome and expensive.

The present invention relates to an apparatus for all'ixing plaster-work to ceilings, especially concrete ceilin s, without the ernployment of screws. Tiis apparatus consists, substantially, of a platform for receiving the mold for the plaster-work. This mold is arranged in a suitable frame in such a manner that it can be raised or lowered and is forcibly pressed. against the ceiling by means of a toothed gearinY or equivalent means. The plaster is fresiily poured into the mold and pressed in this state against the ceiling. Thus the plaster which is in the mold is thoroughly moist when pressed against the ceiling, so that it is im )ossible for the moisture to be suddenly a sorbed out of the parts which come in contact with the ceiling. In consequence of the powerful pressure applied to the plaster work when the latter is pressed against the ceiling the moisture in the plaster is given ofi under powerful pressure to the lowest part of the ayer of concrete, which is thoroughly moistened and then only in a condition to allow the plaster to set against the ceiling. When the plaster in the mold is set, the platform bearing the plaster-mold is lowered, and the freshly-set plaster-work adheres [irmly to the ceiling.

Ornamental cement-work and the like can of course be fixed to ceilings in a similar manner.

In the accompanying drawings, Figure 1 is a side elevation; Fig. 2, a front elevation; Fig. 3, a section through A B in Fi 1, and Fig. 4 a side elevation illustrating t 1e apparatus in action.

The platform (l, on which the plaster-mold is placed, is suitably made of au lc-iron and` pivoted on the rack b. IVith tie rack b a pinion e engages, which can be actuated by means of @car-wheels d c and a crank-handle f. A guide-roller g is n1 1iunied at the back of the rack opposite the tooth-wheel c, the rack working in the guide 7i. The toothed gearing for operating the rack is mounted in a frame comprising extensible corner-columns fi, which are provided with feet c. In order that the frame may be conveniently adjusted, the columns i, as well as the feet, are serrated and are held together by ties l. These ties l can be turned on hinges `m, fixed to the columns fi and locked by pins n.. As accessories to the new apparatus columns o, Fig. 4, which can be raised or lowered, are provided. These columns serve for forming a stage on which. the workman can conveniently serve the platform c.

The action of the new apparatus is as follows: The pins n are removed from the ties l, the ties turned on the hinges m, and the feet 7c placed a ainst the columns i in such a manner that t e platform a, which is in its lowest position, stands at the required distance from the ceiling. Hereupon the ties l are locked by means of the ins n. The columns o, Fig. 4, which are ikewise adjusted IOO IIO

to the required height, are placed so that by means of beams p and boards g a stage can l be formed on which the workman stands and can conveniently work on the platform` (L. The plaster-mold for the piece of work is then put on the platform and the fresh plaster poured into the mold. When. this has been done, the platform a, bearing the mold and the fresh plaster, is raised by turning the crank-handle f and forcibly pressed. against the ceiling. VV'hile the plaster is being pressed against the ceiling the work.- man attending to thc platform. turns the platform slightly around its pivot on the upper end of the rack7 so that during the pressing action the fresh plaster is at the same time rubbed against the ceiling. It will be seen that by means of this apparatus a large surface of the plaster is simultaneously pressed against the ceiling.

When the plaster is set, the platform is lowered from the ceiling by turning the crank-handle in the reverse direction,v the frame pushed farther, and the next part of the plaster-work formed in the same manner, and so on.4

That I'claim, and desire to secure by Letters Patent` is- 1. An apparatus for applying molded plaster-work to ceilings comprising a frame or support, a platform mounted to rotate on the support and adapted to support the plastermold, and means for raising and lowering the platform. on its support to first apply the plaster to the ceiling and then withdraw the platform and` plaster-mold.

2. An apparatus for applying molded plaster-work to ceilings comprising a frame or support, a `fixed vertical guide in the support7 a rack mounted to slide in the uide, gearing for raising 0r lowering the rae and a platform mounted to rotate on the upper end of the rack adapted to receive the plaster-mold. and press the plaster against the ceiling.

3. An apparatus for applying molded plaster-Work to ceilings comprising an extensible frame or support, a fixed vertical guide in the support, a rack mounted to slide in the uide, gearin for raising or lowering the racr and a plat orm mounted to rotate en the upper end of the rack adapted to receive the plaster-mold and press the plaster against the ceiling.

In testinlony whereof' l have af'iiXed my signature in presence of two witnesses.

M(V)R1TZ LAU.

Witnesses ERNST KATZ, ALBERT SUHENK. 

